Underfeed stoker



Nov. 24, 1936.

c. A. WARG UNDERFEED STOKER 4 sheets -sheet 1 Filed Oct. 24, 1930 Jwvento Nov. 24, 1936. c. A. WARG UNDERFEED STOKER Filed Oct. 24, 1930.

4 Sheets-Sheet' 2 Www hm H CH. Wim

Nov. 24-, 1936. c. A. WARG UNDERFEED STOKER Filed ct. 24, 1930 4 Sheets-Sheet 3 Nov. 24, 1936. c. AiWARG UNDEBFEED STOKER 4 Sheets-Sheet 4 Filed Oct. 24, 1930 V Jwvmto %ju 94.

Patented Nov. 24, 1936 UNITED STATES UN DERFEED STOKER Charles A. Warg,

Scranton,

Pa., assignor to McClave-Brooks Company, Scranton, Pa., a corporation of Pennsylvania Application October 24,

10 Claims.

This invention relates to underfeed stokers and primarily to equipment of a character which may be installed in either new boiler plant installations or which may be used to replace stoker equipment in boiler plants which have already been installed and in use.

The stoker equipment in accordance With this invention comprises a front plate to be positioned'over the outer face of the front wall of the fire chamber of the plant With the lower portion of the wall cut away to accommodate a central fuel retort extend'ng rearwardly from said front plate to the* rear fire chamber wall which is formed with a chamber for counterbalance weights for dump g'ates adjacent the side walls of the fire chamber. Between the retort and the dump grates are arranged tuyres extending to a crest over the retort and intermediate grates slope away from the outer ends of the tuyres beyond the crest to the dump grates. Outside of the fire cl'arnber usually to the front is an individual adjustable stoker feed driving unit and preferably near it is an individual blast fan unit for supplying draft to the tuyres, and means are' provided for driving these units either together' or independently.

The retort is fermed of an integral bottom section supporting, a series of top sections on each side; it has a two-sectioned front deflecting plate,

30 the inner section of which is replaceable by breaking away the front portion only of the front wall without interfering With the outer section or that portion of wall which is above such outer section of the plate. The retort also has o a rear defiecting plate which rises from the bottom wall of the retort to the rear fire wall above the top retort sections, and is supported so as to allow for expansion Without stress on the fixed parts.

40 The. tuyres form a continuation of the side walls of the retort to the crest and then slope downwardly, grate sections and dump grates beyondiforming a continuation of the outer walls of the tuyres. The tuyre blocks have staggered air openings arranged so thatopenings of adjacent blocks do not coincide, the arrangement being such as toafford a large draft space with relative- 1`y small openings Well distributed over the tuyres.

Theintermediate grates and dump grates are also provided with draft openings and dampers control the drafts to these grates thus providing for increased emciency of combustion The outer portons of the tuyres and the grates are formed with outWardly directed ribs continuous from the tuyre blocks along the sections of the grates 1930, Serial No. 491,025

for distributing and guiding the fuel over the grates and effecting a raising of the burning fuel from the corrugations formed by the ribs thereby cutting down the area of contact of the fuel with the grates so that they will not burn out 5 as fast as they would if their surfaces Were fiat.

The stoker driving unit as illustrated is arranged to vary the rate of fuel feeding into the retort and also has adjustable means for the pusher rod for distributing the fuel in the retort, and the pusher rod shoes on said rod are also adjustable within limits and are guided so as to prevent bowing of the rod. In many installations the fuel feed mechanism and the blower are driven by a single steam or electric motor but where the blower is located at the side of the furnace it almost invariably is driven by its independent motor often of a different type from the fuel feed motor.

The stoker parts are generally formed in removable sections to provide for Variations in temperature'of the parts in different positions with respect to the burning fuel and also for the easy replacement of parts which have to be renewed, for example, while the ram case is bolted directly and securely to the retort neither is fastened to the stoker front, but on the contrary the junetion rests slidingly on a ledge of the front and space is allowed for expansion without placing any lateral stress on the stoker front. The top retort sections are bolted to the bottom section, the intermediate grate bars resting on the side walls of the draft chamber and side supporting frames between said wall and the retort and the blocks of the tuyres are supported on said side supporting frames and the top retort sections. Access to the plenum chamber is permitted by a readily remo-vable closure in the ash pit wall. A tuyre rod engages eachblockto retain the tuyrcs in place and also the intermediate grate sections which have interlocking engagements with the tuyre blocks. The dump grate parts are also removably mounted in the stoker and the parts of the feed driving unit and draft fan are likewise replaceable, and means are provided to prevent improper assembly of the adjustable sections. Special provisions are also made to' prevent loss of air pressure and at the same time to avoid any sifting of the fine fuel from` either the hopper or the retort to lose fuel or to so il the surroundngs.

Further features and objects of the invention will appear from the following specification, accompanying drawings and as pointed out in the claims.

In the drawings in which like characters of reference designate corresponding parts throughout the several views;-

Figure 1 is an elevation of one side of a stoker front and a sectional View of the other side of the stoker, this section being taken on line I-l of Figure 2.

Figure 2 is a longitudinal vertical section on the center line of the stoker, line 2-2 of Figure 1, also showing the stoker fuel hopper and stoker feed driving unit in front of the stoker in section and partly in elevation.

Figure 3 is a ragmentary sectional View taken on line 3-3 of Figure 2 showing a portion of the stoker grates in plan.

Figure 4 is a side elevation of the stoker feed driving unit, fan and fuel hopper.

Figure 5 is a front elevation thereof.

Figure 6 is a plan view of the stoker feed driving unit.

Figure 7 is a sectional View of a grate section, taken on line 1--1 of Figure 8.

Figure 8 is an enlarged end elevation of the grate section shown in Figure '7, parts being broken away and shown in section on line 8-8 of Figure '7.

Figure 9 is an enlargedside elevation of a tuyre block.

Figure 10 is an end elevation of the tuyre block shown in Figure 9.

Figure 11 is an enlarged plan View of a dump grate section.

Figure 12 is a side elevation of the dump grate section shown in Figure 11.`

Figure l3'is a plan View of a clamp member for the dump grate section shown in Figures 11 and 12.

Figure 14: is a rear end View of one of the retort fuel pusher shoes showing its relation to the retort, the retort being shown in section.

Figure 15 is a side elevation of the pusher shoe shown in Figure 14.

Figure 16 is a plan View of the same pusher shoe.

Figure 17 is a staggered sectional View through the ram cylinder showing the ram piston engaging ring. i

Figure 18 is a transverse sectional View through the ram connecting rod adjacent to the forward end thereof.

Figure 19 is a sectional View taken substantially on line lS--IQ of Figure 2.

In general the stoker disclosed, comprises a stoker front !5 which is mounted on the front wall !5 of the fire chamber, retort members !1, tuyres !8, grates s and dump grates 20 and other parts hereinafter set forth, extending from stoker front |5 and front wall IE to the rear fire chamber wall ZI; and outside of stoker front !5 are the stoker fuel hopper 22, stoker feed driving unit 23, fan 24 and air duct 25 leading therefron to the draft chamber.

stoker front !5 consists of a pair of main plates designated by the same numeral, !5, bolted together and to a top plate IE and to two side plates |5 which in turn are Secured to front wall I@ and side walls M, respectively, of the fire chamber. It is provided With two fire doors (one opening 25 of which is shown in Figure 1) for access to the grates in the fire chamber on either side of retort members H. There are also a pair of doors (one opening 21 of which is shown in Figure 1) for access to the ash chambers. There is also an opening 28 therein for the air duct 25 from blo wer fan 24 and a front siftings clean-out door 29, indicated in Outline in Figure 1,

providing access to the draft chamber under retort I'I, tuyres l8 and grates 19. The stoker front also has control members, other parts and openings referred to hereinafter.

Retort members l'l consists of a lower section 39, the front end of which extends into an opening 3| in stoker front !5 and is provided with a fiange 32 which engages interior rest 33 on the stoker front for supporting it with a space between the fianges of the ram case and retort, I IT and 32 respectively, without placing any lateral Stress on the stoker front. The retort is thus supported so as to have a clearance in openings 3l and the retort and is Secured to the ram case by means of bolts l|8 passing through the fianges of these members. These bolts are not in contact with the stoker front which is cut out as indicated at |2`| for them so as to permit free movement of this end of the retort in opening 3! of the stoker front to take care of expansion due to variations in temperature as the support for the ram is fixed, the ram being connected to the stoker feed driving unit 23 which is fastened to a concrete foundation, the stoker front is fixed and there must be room for movement due to expansion and contraction. The rear end 34 of this lower section is supported on a pair of spaced brackets 35 on the rear frame plate 36 which is mounted in rear wall 2| of the fire chamber; these brackets also permit longitudinal movement of the end of the retort thereon to take care of the expansion and contraction of the retort since the retort is fastened at its front end as just stated. This retort section 30 has diverging side walls 31 extending upwardly from its bottom Wall 38 which slopes upwardly from stoker front [5 towards the rear of the fire chamber to a point 39 where it slopes upwardly at a steeper angle. A rear deflecting plate 49 is a continuation of this bottom wall 38 extending upwardly therefrom to rear wall 2| Where it has a laterally extending projection which provides an anchoring means therefor and a pair of fianges 4l, the upper ends of which rest on top of rear frame plate 36 to support it in proper position during the assembling of the stoker.

Retort I'I has top members consisting of front sections 42 extending upwardly from side walls 31 of lower section 38 and extending rearwardly from the stoker front opening 3l through fire chamber front wall I 6. Rearwardly from these front sections 42 are a plurality of retort top intermediate sections 43 followed by retort top rear sections 44 which extend beyond rear defiecting plate 4!) and end adjacent to rear frame plate 36. These top sections have their en'ds abutting and are assembled on the lower retort section by means of bolts passing through lugs 45 extending laterally outwardly from the sections as shown in the sectional portion of Figure 1.

Above the retort top front'sections 42 is a front deflecting plate composed of two sections,

a front section 46 extending rearwardly and upwardly from stoker front opening 3l preferably' more than half way through wall |6 and ending in an upwardly extending anchoring fiange 41. From this section 46 a rear section 48 extends to the inner side of the fire chamber wall !6, this section being anchored in thewall by means of a similar flange 49 which is arranged in substantially abutting relationship with flange 41 but is not fastened thereto. This two section Construction of the front deector plate provides for reaoeao're placement of the rear section 48 by merely breaking a small portion of the fire chamber wall'.

structure from? around it for riemoval and. replacement when this section burns out and` has to be replaced, without having to replace the enire deflector plate.

In installing the parts in the fire chamber of a plant which has already been in use it isonly essential to break away the base, of the front wall !6 of the fire chamber to a. short distance above the retort l1, likewise the rear wall 21. Walls or masonry partitions, 50' and 5! at the, rear for supporting the rear frame plate 36 and providing an enclosed chamber 52, andtwo side i longitudinal walls 53, one at either side of retort !1, are erected. These walls in conjunction with' a portion of the lower part of stoker front |5, rear frame plate 36, and' damper partition 54 mounted on the two side walls 53 provide a retort or plenum chamber 55 of the stoker.

The front siftings clean-out door 2 9 at the side' of the ram is to'o small for a man' to get into the retort or plenum chamber so provisions are made for him to enter through one of the ash doors, 21, as shown the left hand one, and to enter this chamber through a doorway 53l in the longitudinal wall 53, as it would be impossible also for himto climb over' this wall-because of the iron partition and other structure above it. This wall 53 therefore terminates a distance from stoker front 15 and an access door frame 532 is fastened in the space provided therebetween, the frarne being Secured by bolts 533 to the bottom fiange of the damper partition 54 above it and by bolts 534 extending through a fiange 535 of the frame and a flange 536 on stoker front !5. The base. and other end o-f the frame may also be suitably Secured to the floor and end .of wall 53 in an air tight manner. Frame 532 has an inwardly extending fiange 531 surrounding the opening therethru and in its outer face has a groove 538 which contains packing for engagement with the access door 539 to provide an air tight closure. Door 539 is a little smaller than the inner sides of frame 532 so as to engage flanges 531 thereof and the packing in groove` 536; On the inner face of thisdoor is afiange 546 which fits inside of flanges 531 of frame 532 insuring proper closure of the doorway. To secure door 539 in place and providemeans for handling it, the door has a pair of handles 541, each provided with a shaft 542 which extends through apertures in door 539 adjacent to the ends thereof, and on the inner side of the door these shafts are squared to receive latch members 543 which are keyed thereon. The extending ends 534 of these latch members are provided with cam faces 545 for engagement with the inner faces of flange 531 at the ends of the door frame. The door is readily Secured in the frame by turning handles 54! so that cams 545 will draw the door tightly against the packing in groove 538 and is as readily removed by turning these handles in the opposite direction freeing latches 543 of fianges 531.

Damper partitions 54 extend from the stoker front [5 where their ends are bolted to a flange 56 and the lower edges thereof' rest on extensions 536 on the sto-ker front to the rear frame plate 36 where the ends are bolted to similar flanges and the ends of the partition are also provided with end anges 58 which are fastened to the rear frame plate. These partitions have a plurality of slide damper openings 59, two being shown, each having upper and lower slide damper'guides. 60 and' front and rear stops 61: which limit the movement of the slide dampers 62: Dampers 62 are provided with apertured lugs which are connected with rods 63 extending through stoker front 15 and having handles 63 for controlling them to regulate the draft from chamber 55 to dump grates 20 at the outer sides of the, draft chamber 55 of the stoker.

There are also two side frames 64 which extend from stoker front 15 to rear frame plate 36 and these frames are fastened at their ends in a similar manner, in intermediate positions between, damper partitions 54 and the sides of retort l1 as shown in the sectional portion of Figure i. Between damper partitions 54 and side frames 64 are arranged butterfly dampers 65, cne of which is shown in closed position With its side. engaging the upper slide damper guides 60 as stops therefor. on shafts 65 journaled in rear frame plate 36 at one end and in stoker front !5 through which its other end extends and upon which is mounted an Operating handle 65 The draft to grates l9 from draft chamber 55 is regulated by means of this damper, handle 65 being provided. with an engagement member 65 adapted to yieldingly engage .any one of a series of stops or apertures 65 on the stoker front, whereby the butterfly damper 65 may be held in various positions.

The upper edges of damper partitions 54,rsideframes 64 and the retort top sections 43 and, 44 provide supports for the sections of grates l9 and tuyres !8. The sections 66 of grates' [9 are wide in comparison with their length and have downwardly extending end flanges 61 and 68 which rest on the upper edges of damper partitions 54 and side frame 64 respectively, the latter being channeled in their top edges having side members 69 thereof which engage the inner sides of flanges 63 and prevent the sections from sliding downwardly. As shown in Figures 1, 7 and 8 each section 66 has a pair of side fianges 10 whichare' slotted at 1l so as to receive a side flange 12* on the damper partition 54. One side of each section is slotted at 66 and the other side provided with a tenon 66, this arrangement providing a .snug connection between the sdes of the assembled sections which will not permit ashes to sift through nor a leakage of air. With this construction it is essential that the sections of grates IS be assembled before the tuyre blocks l8, or that tuyres I 8 be removed before sections of grates !9 can be removed as each of the sections 66 is slotted at its upper end at 13 for the reception of the end of a number of tuyre blocks 14 of' tuyres 18.

Tuyre blocks 14 as shown in Figures 1, 9 and 10 have flanges 15 which engage the Channels of side frames 64 and side members 16 thereof' and endfianges 11 on these blocks extend'ng below the upper edge of retort sections 43 and 44 and engage lateral flanges 18 thereon. Each tuyre block 14 is provided with a web 19 which extends downwardly and is apertured at 86. Top retort sections 43 and ,44 have fianges 8! which extend between a number of the tuyre block webs` 19 and have similar apertures in` alignment with apertures 86 of' webs 19. extend through these apertures, into apertures in rear frame plates 36 as shown at 83, and through stoker front |5 ending in handles 84'by which these rods may be withdrawn when it is desired to remove any of the tuyre blocks 14 or grate sections 66.

Tuyre blocks 14, as shown in Figures 1, 2, 3, 9

Dampers 55 are mounted' Tuyre rods' 82' and 10 .are provided with air opening& except two front end blocks which are blank and the rear side of rear blocks 86 which are substantially double the width of the other blocks and cut away at their outer sides .and inwardly flanged at 81 to engage the upper end of rear defiecting plate 40. The rear or outer side of these blocks 86 are blank and inner sides of each have an opening 88. Blocks 14 are each provided with two series of openings, one series on each side of the crest of the bars. The series facing the retort consists of an even number of openings on one side of the block and an odd number of openings on the other side as indicated at 89 and the other series at the end of the block extending beyond the crest and facing away from the retort likewise consists of even and odd numbers of open- 'ngs on the sides of the block as indicated at 90. These air openings are so arranged that openings of one block will not coincide with openings of an adjacent block and they afiord a maximum draft from plenum chamber 55 for the fuel coming over the tuyres l8 directly from retort 11, no damper being positioned in the passageway between side frames 64 and the sides of retort I 1, the draft being regulated by the supply of air from fan 24 to draft chamber 55.

Tuyre blocks 74, 85 and 86 are also provided with ribs 9! which when the grates are assembled are arranged in two equally spaced series either side of the retort IT, the ends of the blocks slope ing away from the retort toward the side walls of the fire chamber. Sections 66 of grates !9 have ribs 92 which form continuations of ribs 9! and increase in size in the direction of progress of the burning fire, that is as they extend away from retort I?, and likewise sections 93 of grates 20 are each provided with two ribs 94 which are coextensive with ribs 9| .and 92 of tuyres I8 and grates !9. This arrangement of the ribs on the grates efiects a guide for the fuel and an even distribution thereof over the grates and as its burning progresses as it moves along the grates the increasing of the size of the ribs effects a lateral movement or turning of the burning fuel affording a more even combustion thereof. The ribs also prevent fuel from lying flat on the metal of the grate bars eifecting a raising of the fuel from the grooves thereby decreasing the area of contact therewith and consequently increasing the life of the grates in comparison with fiat grates which soon burn out due to more uniform contact with the burning fuel.

The grates l9 and 28 are also provided with air openings for the draft controlled by butterfly dampers 85 and slide dampers 59 respectively. Openings 95 in grates |9 are .arrang'ed to extend upwardly through the ribs 9l, and openings 96 in grates 28 extend through ribs 94 and through intermediate portions in the staggered relationship.

The arrangement of the grate surfaces and draft openings afford eficient combustion of the fuel .as it passes outwardly from the retort so that as the fuel progresses to the outer ends of grates 20 it is reduced to ashes before dropping into the ash chambers 91 at the outer sides of walls 55.

As the spent fuel accumulates on grates 20 it is occasionally necessary to dump these grates and to provide for this the section 93 thereof at each side of retort l'l are mounted on dump grate shafts 98. These shafts are square in cross section and provided with bushings which are journaled in bosses in stoker front I 5 and rear frame plate 36 through which they extend as indicated at 99 in the rear frame plate end.

On these shafts 98 between the dead plates o, just inside of doors 26, and the rear wall 2| of the fire chamber are mounted the grate sections 93, shown in detail in Figures 11 and |2, of the dump grates 20. The mounting of these sections consists in integral hub portions [02 which have cylindrical surfaces |03 to close as far as possible the space between the sloping grates l9, as best shown in the sectional portion of Figure 1.

Hub portions |02 have rectangular slots [04 to receive the upper half of the dump grate shafts 98 and lower cooperating caps !05 shown in Figures 1 and 13, are similarly slotted and have cooperating cylindrical surfaces lll6. Caps |05 have V projections !05 which extend upwardly and cooperate with notches !02 in hub portions !82. Bolts IO'I pass through aligned openings in sections 93 and the bottom caps and receive nuts 198 for securing the sections assembled on shafts 98; the heads of these bolts are positioned in deep pockets filled with ashes and protect the bolt heads from the effects of the heat and also prevent leakage of air.

Extending forwardly from these hub portions !92, under each of the grate sections 93, and integral with these parts are vertical triangular reinforcing webs HD extending from the lower portions of the sections between the ribs. It will be noted that the holes 96 in these portions of the grate sections are staggered on either side of these web members and as close thereto as possible.

On the rear end of each dump grate shaft 98 within the chamber 52 formed in the lower portion of the rear' fire chamber wall 21 is a counterbalancing weight lll secured to the shaft by means of a set screw ll2. chamber 52 is large enough to permit the counter-weights to swing upwardly to a horizontal position in the direction of the retort when the grates are to be dumped. The weights are of such proportion as to overbalance all the dump grate bars but are overbalanced by the weight of the grates When they are loaded with the ashes that accumulate thereon between dumpings.

These weights on shafts 98 thus facilitate the operation of the dump grates by means of a handle which is applied to the front ends l|3 of shafts extending through the stoker front I5 when it is essential to dump the grates. In order to prevent the grates from swinging freely a latch ll4 is provided inside retort front I 5 having means for engaging shafts 98 from turning. When it is desired to dump these grates a handle H5 on the outside of the stoker front is operable to disengage latch ll4.

In order to feed the fuel from stoker hopper 22 to retort IT a ram case I |6 is mounted in an intermediate position to the front of stoker front l5, fiange l H of the ram case being secured by bolts l !8 to the retort as hereinbefore set forth. Hopper 22 is mounted over ram case l|6 by bolting flanges l|9 on hopper 22 to fiange surrounding an upper opening in the ram case. The ram case thus afiords a direct passageway for fuel from the hopper to the retort, and a ram !21 therein operates to feed the fuel to the retort in conjunction with a pusher rod !22 and a plurality of pusher rod shoes [23 adjustably mounted therecn along the bottom wall 38 of the retort !09 which afterwards become which shoes operate to distribute the fuel in the retort.

Hopper 22 is shown composed of sections having fianges !24 secured together as indicated.

- It is provided with a, bar hole !25 affording access to the passageway to retort and a bar hole cover !26 normally closes this hole.

Pusher rod !22 passes through a bushing !28 Secured in an aperture through the downwa'dly extending portion of lange !!T on ram case !!6. The pusher rod extends adjacent to the bottom wall 38 of the retort and its rear' end !29 extends through a similar bushing !39 mounted in an enlarged portion of opening !30 in the portion of this wall sloping upwardly beyond point 39. Bushings !28 and !30 are each provided with a pair of laterally extending apertured anges and stud bolts extend therethru for securing the bushings in their respective positions. These pusher rod bushings prevent loss of fuel at the front which would mean dirt sifting through onto the floor outside the stoker front and air at the rear from the plenum chamber. The rear end 34 of the lower retort section is recessed as shown at !3! so that end !29 of rod !22 is free to move therein to a point between brackets 35 as it does when the ram and rod are set to operate to a maximum rearward stroke.

Pusher rod shoes !23 as shown may vary in size, and are Secured to pusher rod !22 by means of set screws !32 preferably with their heads entering sockets in the upper inclined faces !33 thereof; the relative positions of the shoes may be changed on rod !23, their distance apart, and also arrangement of different sizes shoes.

It will be seen that inclined faces !34 of these shoes are at such an angle that when the shoes are pushed rearwardly the fuel will be moved in that direction and on the return stroke the fuel will not follow the shoes but will slide up over faces !33 thereof, the fuel coming down from hopper 22 into ram case !6 preventing any movement in that direction. The lower faces !35 of these shoes are grooved at !36 to grind any siftings which may get under the shoes and otherwise might obstruct the free movement of the shoes.

In order to prevent the pusher rod from bending in retort which may be of considerable length one or more of the pusher rod shoes, one shoe !23! as shown in Figures 2, 14, 15 and 16, may be provided with !ateral extensions !232 and pusher shoe guides !233 are secured to the retort by countersunk head bolts !234 so as to engage these lateral extensions at each side to prevent the' rod from bending. These extensions have forward sloping faces !235 and rearward diverging walls !236 which also assist in raising the fuel in the retort on their forward stroke.

w Pusher rod !22 is moved by ram !2! which is constructed in the form of a piston which is to be reciprocated in the cylinder !39 of the ram case extending forwardly from retort In order to prevent real fine fuel from creeping through at the top of the ram and falling to the floor, cylinder !39 is provided with a groove !39l which houses a ram packing ring !392 formed of a casting cut, expanded and turned so as to spring against the outer cylindrical wall of the ram to prevent the ram from pulling such fine fuel back into the cylinder of the ram case on its outward stroke which would fall through a slot !40 in the bottom portion thereof. This ram packing ring clears slot !40 by about an inch on each side and the two ends of the groove are closed by stop blocks !393 Secured thereon by means of screws !394. The face of the ram piston is provided with a flange !43 which assists in moving the fuel on the forward stroke and on the reverse stroke covers slot !40 in cylinder !39, the upper portion of this fiange extending only slightly beyond the face of the piston permits of a wide range of movement of the piston for varying the amount of fuel to be fed by the ram into the retort on each rearward stroke thereof. Through slot !49 in the lower rear portion of cylinder !39 extends a projection !4! which is fastened to ram piston !2! by tap bolts. This projection !46 has laterally extending projections providing a pusher rod guide !44 for supporting a pusher rod adjusting strap !45, the rear end of which strap is pivoted at !46 to pusher rod !22. This strap is provided with a series of apertures 'i which are adapted to receive a pusher stroke adjusting pin !48, shown in Figure 2 in the first of these apertures.

When ram !2! is moving inward projection !4! thereon moves pusher rod !22 and shoes !23 thereon in a feeding direction and on the return stroke the projection moves until it engages the end !49 of the adjusting strap !45 and then moves rod !22 and shoes !23 outwardly with it. The stroke of rod !22 is diminished by changing pin !48 to any of the other holes l4'! shown and when in the holes nearest the connection with rod !22 the stroke is a minimum,--when farthest away, as shown, the stroke is a maximum. To the end of the pusher rod guide !44 at the outer side is Secured a pusher adjusting pin guard !44! by means of a pair of bolts !442. This guard member has a projecting end !443 extending outwardly from the retort so that in case it is desired to change the position of the pusher stroke adjusting pin it will be impossible to insert it through any of the apertures !41 on the side of guide !44 occupied by the projecting end !443 of the guard which covers them.

Driving unit 23 for Operating ram !2 and pusher rod !22 consists of an enclosed case protecting the driving mechanism from all dust, breakage, etc. and is mounted on a motor and crank case base !50 which is Secured to a concrete foundation in .front of ram case !!6 in a position for its open flanged rear end !51 to be bolted to an end flange !52 on the ram cylinder !39. The driving mechanism includes a drive shaft !53 journaled in a worm housing !54 at right angles to a second worm housing !55 in which are double worm reduction gears driving a worm gearin a. third housing !56 of the casing. From the latter worm gear a crank !51 extends carrying a journal !58.

A connecting rod !59 extends between crank journal !58 and a wrist pin !66 in the ram piston 2! which is adapted to impart strokes to the ram of different lengths so that the amount of fuel fed by the ram into the retort by each stroke may be regulated. This connecting rod has a front bearing !6! and hearing cap !62 with brass linings !63 and the cap is Secured to the rod by bolts !64. The rear end of the connecting rod is likewise provided with a brass hearing lining !65. The front end of connecting rod !59 has a tubular extension !66 of rectangular cross section into which a rod 16'! of similar cross section that is Secured in the rear end of the connecting rod by means of a bolt !68, is telescopically engaged so that the free end of the tubular extension !66 can engage the shoulder provided at the junction of rod !61 with the rear end of connecting rod !59 to move ram 2! on the feeding stroke in the direction of retort !1.' Tubular member !66 of the connecting rod is provided with a series of five apertures !69 extending downwardly therethru and rod !61 has a cooperating downwardly extending slot !10. A ram stroke adjusting pin 41! may be positioned in any desired aperture and extends through slot !19 in rod !61 so that on the outward movement of the connecting rod tubular member !66 the driving unit will withdraw this section of the connectng rod until pin !ll engages the forward end of slot !19 and thereafter rod !61 will be drawn with it for the return stroke of ram !2!. In the position shown pin !1! is in the second aperture so that ram !2! will be actuated for a long stroke. When the pin is in the first aperture the stroke of the ram is a maximum, being substantially the full stroke of crank 51 of the driving mechanism and the minimum stroke provided for is the flfth aperture. In order to prevent pin !1! from being positioned through an aperture !69 whenthe tubular portion of the connecting rod and ram are at the far ends of the crank strokes with respect to each other the end of rod !61 of the connecting rod is recessed at !61l and provided with an end abutment !612 which extends upwardly a short distance and tubular member !66 is provided with laterally extending grooves !613 in the upper portion thereof; in groove !613 a ram adjusting pin guard !614 is slidingly mounted so as to be received in recess !61! of rod !61 entirely when the tubular member !66 and rod !61 are telescoped together and to be more or less withdrawn from the recess according to the amount the tubular member is withdrawn. An extension !615 of the pin guard !614 engages abutment !612 so as to prevent this guard from being withdrawn from the end of rod !61 when tubular member !66 is moved outward to its fullest extent by crank !51 with respect to rod !61. This guard extending beyond the end of rod !61 is adapted to cover apertures !69 and prevent the improper insertion of pin It will be noted that opening 5! has a slot !5! extending therefrom to provide for movement of projection !4! on ram !2! thereinto when the ram is set for a maximum charge stroke.

Access to adjusting pin !1! in the crank case of driving unit 23 is provided for by opening the crank case cover !12 which is hinged to the case as shown at !13. The crank case is also provided with another opening !14 for access to the bearing !6! and cap !62 therefor, this opening being closed by a plate !15 fastened by bolts !16.

An electric motor !11 is mounted on the outer portion of base !58. On one end of the motor shaft !18 is mounted a sprocket !19 for driving a chain between this sprocket and a sprocket !Bl on shaft !53 of the driving unit 23. This drive between motor !11 and driving unit 23 is enclosed in drive ch-ain guard !82 suitably secured to the driving unit. On the other end of motor haft !18 are mounted the blades of fan 24 the casing of which has side base members !83 secured to the floor so as to position the fan alongside the motor and driving unit base !50. It will be noted that the intake opening !84 of the fan extends outwardly from the rest of the equipment and the outlet end is arranged to direct the air blast toward the stoker where it communicates with the outer end of air duet 25 positioned alongside the driving unit base !59 then leading downwardly beyond a point !86 below the floor line and into opening 28 through stoker front !5 to draft chamber 55.

In operation motor !11 drives fan 24 at a speed to` furnish the required air bl-ast to tuyres !8 and through the chain drive !89, etc., double worm reduction gears, crank !51 and connecting rod !59 operates to reciprocate ram !2! and pusher rod !22 with shoes !23 thereon for ramming charges of fuel from hopper 22 into retort !1 and feeding same over tuyres !8, grates !9 and dump grates 29. The amount of fuel fed at each stroke is regulated by adjusting the ram stroke adjusting pin !1! in the apertures !69 and !10 of the telescopic connecting rod !59 between crank !51 and wrist pin !69 of ram !2! and the stroke of pusher rod !22 is adjusted by changing the position of pusher stroke adjusting pin !48 in apertures !41 of the pusher rod adjusting strap !45 so as to give the pusher rod shoes !23 the required stroke for distributing the fuel charge in retort !1.

In the normal operation of the stoker the full air blast is directed through tuyres !8 and slide dampers 62 and butterfiy damper 65 are closed. But when dump grates 20 become loaded with an accumulation of spent fuel, handles 65 are turned to open butterfly dampers 65 and handles 63 are operated to open slide dampers 62 to provide a draft through grates !9 and dump grates 20, respectively, so as to burn the fuel on these grates briskly for a few minutes before grates 26 are released to dump the spent fuel. Latches 4 are then released by handles !!5 permitting grates 20 to dump, and dump grates 20 are controlled during the dumping by means of an Operating handle applied to the outer ends !!3 of dump grate shafts 98 for controlling the dumping of the grates and their return to normal horizontal position which is facilitated by the aid of counterbalance Weights !!I. on the rear ends of these shafts. Dampers 62 and 65 are then closed and the stoker is again in normal Operating condition.

What I claim is:

1. An underfeed stoker including a stoker front, a rear frame plate, a retort extending from the stoker front to said frame plate and supported by said front and rear frame plate, a damper partition secured to said front and rear frame plate at either side of said retort, a side frame secured to said front and rear frame plate at either side of said retort between said damper partitions and said retort, grate sections arranged side by side and having their ends supported by said damper partitions and said side frames, blocks of tuyres arranged side by side and having their ends supported by said side frames and said retort, and dump grates pivotally supported by said stoker front and rear frame plate at either side outside of said damper partitions.

2. An underfeed stoker including a stoker front, a rear frame plate, a retort extending from the stoker front to said frame plate and supported by said stoker front and rear frame plate, a damper partition secured to said front and rear frame plate at either side of said retort, a side frame secured to said front and rear frame plate at either side of said retort between said damper partitions and said retort, tuyre blocks supported by the retort and the side frames and grate sections supported by the side framesand damper partitions.

3. The stoker of claim 2 including a fuel hopper and ram case, the forward end of said case being fixedly mounted in front of said stoker front and having its rear end connected with said retort to deliver fuel thereto, said retort being freely supported by the front and rear frame plate.

4. An underfeed stoker for -a fire chamber including front and rear walls, a fuel retort extending from the front of the fire chamber to the rear wall thereof and freely supported by said walls whereby during expansion or contraction the retort may move with respect to said walls, and a rear deflecting pl-ate Secured only to the rear wall and resting on the floor of the retort.

5. An underfeed stoker including a fuel retort comprising a lower troughlike section and a plurality of top sections resting freely on the lower section and extending upwardly from each side thereof, and a front defiector plate resting on the top sections at the front end of the retort comprising -a front section extending from the front thereof inwardly and a rear section extendng from the rear end of the front section inwardly, said defiector sections having fianges to engage the front wall of a fire chamber.

6. An underfeed stoker including a stoker front having a retort opening therethru, a rear support,

`a retorthaving its rear end resting on said rear support and having its front end extending thru said opening and resting on said stoker front, a ram case outside the stoker front and fixedly mounted at one end, said ram case being connected at the other end to the front end of said retort whereby the retort moves with respect to said rear support and stoker front during expansion and contraction due to changing temperatures.

7. An underfeed stoker including a stoker front having an opening therein, a rear frame plate, a ledge on said plate, a retort extending thru and resting freely in said opening and also resting on said ledge, a side frame supported by said front and rear frame plate and tuyres locked to said retort but resting freely on said side frame whereby said retort is entirely freely supported to allow for expansion and contraction.

8. An underfeed stoker including a, stoker front having an opening therein for receiving a retort, a rear frame plate, a ledge on said plate, a central retort resting freely in said opening and on said ledge, a rail secured to said front and to said rear plate, a side frame between said rail and said retort and supported by said front and said rear plate, grates transverse of and resting freely on said rail and side frame, tuyres forming continuations of the side walls of said retort, means for looking the tuyres to said walls, said tuyres resting freely on said side frame and each having a ledge overl-apping said grates, said grates having downwardly extendng webs for interlocking With said rail.

9. The device of claim 8 including dump grates forming continuations of said grates, means cooperating with said rail for providing -a partition between the space under the retort and the space under the dump grates, dampers in said. partition for controlling the flow of air between said spaces, and damper means between the rail and the side frame for controlling the flow of air from said first mentioned space and said grates.

10. The device of claim 8 in which said side frame consists of a plank-like member mounted a with its edges in an upright plane and having a channel along its upper edge, downwardly extending supporting lugs on said tuyres and on said grates resting in said channel whereby said grates and tuyres may have free movement longitudinally of said frame but are prevented from moving laterally thereof.

CHARLES A. WARG. 

